Merge pull request #6 from adam-vessey/7.x

Catch exceptions from ingest.
Merge pull request #7 from adam-vessey/7.x

Alter schema for the introduction of the error state.
Merge branch '7.x' of git://github.com/discoverygarden/islandora_batch into 7.x
Add ability for php functions to be registered in the core batch method.